As shown in FIG. 1, a bone fracture 3 occurs to a femoral neck 2 that defines a boundary between a femoral head 4 and a femoral shaft 5. A greater trochanter 6 and a lesser trochanter 7 are located on the side of the femoral shaft 5. As shown in FIGS. 2 to 4, a conventional internal fixator 101 for repairing a femoral neck fracture includes an intramedullary nail 102 passed into a medullary cavity of a femoral shaft 5, and a lag screw 103 that connects a femoral head 4 to the femoral shaft 5 (see Patent Document 1, for example). The lag screw 103 is passed into a through hole 104 formed in the intramedullary nail 102 from the threaded front end thereof so that the front end thereof is fixed in the femoral head 4, and the rear end thereof is supported in the through hole 104.